Climate Update: Investigating Differences between Surface & Satellite Data

[Andre]

http://www.agu.org/pubs/crossref/2009/2009JD011841.shtml

One can wonder how all these "crackpot" manage to get through "peer review" but anyway: [/cynism off]

The differences between trends observed in the surface and lower-tropospheric satellite data sets are statistically significant in most comparisons, with much greater differences over land areas than over ocean areas. These findings strongly suggest that there remain important inconsistencies between surface and satellite records.

http://hurricane.atmos.colostate.edu/Includes/Documents/Publications/klotzbachetal2009.pdf

From the conclusion

The differences between surface and satellite data sets tend to be largest over land areas, indicating that there may still be some contamination because of various aspects of land surface change, atmospheric aerosols and the tendency of shallow boundary layers to warm at a greater rate [Esau, 2008; Christy et al., 2009]. Trends in minimum temperatures in northern polar areas are statistically significantly greater than the trends in maximum temperatures over northern polar areas during the boreal winter months.

So we actually see the most warming due to decrease in winter cooling in the northern land stations. Apart from all the posible 'natural' causes, would it be an idea to investigate if the weather station get an artificial bias from direct human activities not observed by satellites, See for instance this.

Another detail:

However, as summarized in Christy and Norris [2009] and in several other recent papers, [e.g., Christy and Norris, 2006; Christy et al., 2007; Randall and Herman, 2008] there is a documented spurious warm shift in RSS data around 1992 that is the source of virtually all of the difference between the two satellite data sets. Thus, the closer agreement of RSS with the surface temperature data sets is likely largely due to this spurious jump.

 

[Xnn]

Of course one of the problems with satellites is that they have to look thru the entire atmosphere in order to measure surface temperatures and the atmosphere is not uniform around the globe. It would be interesting to see a detailed technical discussion of exactly how temperatures are inferred from the sensors. However, it's not too difficult to imagine that land and water surface temperature measurments present unique challenges and probably should not be measured with the same set of assumptions.

Mount Pinatubo errupted in June 1991. It took the ash several months to disperse around the globe. The sulfate aerosals persisted for a longer period of time. These also present obvious challenges for satellites meauring surface temperatures and could explain the shift around 1992.

I was only able to read the abstract and the quoted sections. I have a question about the part about trends in northern polar minimum temperatures in northern polar areas being statistically significantly greater than the trends in maximum temperatures during the winter: Are they referring to the actual temperature or the anaomaly?

Obviously thin seasonal snow cover is present during large parts of the winter which may present yet another set of challenges for satellites and researchers.

I understand that a lot of skeptics blame the urban heat island effect for surface stations showing warming trends. However, there aren't that many urban areas in Siberia and especially not in the northern polar regions. So, the fact that they are measuring most of the warming where one would least expect to see urban heat islands causes me to dismiss such concerns.

 

[Andre]

I was only able to read the abstract and the quoted sections.

http://hurricane.atmos.colostate.edu/Includes/Documents/Publications/klotzbachetal2009.pdf

I understand that a lot of skeptics blame the urban heat island effect for surface stations showing warming trends. However, there aren't that many urban areas in Siberia and especially not in the northern polar regions. So, the fact that they are measuring most of the warming where one would least expect to see urban heat islands causes me to dismiss such concerns.

Now what it the observation post is next to a well heated cabin while steam pipes run close to them to cause that heating? Can you dismiss that?

 

[mspelto]

The arctic temperatures as measured by satellite and noted by http://climate.uah.edu/25yearbig.jpg" NASA and RSS show the warming. The link is for the 25 year mean anomaly from UAH, certainly a conservative value. The low number of stations causes a bias for groups such as HADCRUT that do not use the satellite temperature data. Thus, it is not weather station based, so forget the silly notion of cabin bias.

 

[sylas]

Now what it the observation post is next to a well heated cabin while steam pipes run close to them to cause that heating? Can you dismiss that?

Yes. It's a strange speculation not really worthy of much attention, and distracting an otherwise worthwhile thread. But as it turns out, I have investigated the alleged problems with land stations, and shown that confining oneself to stations rated as "class 1" by enthusiasts who rate stations for siting issues make negligible difference to the anomaly calculations. NOAA has done a similar estimation. You can dismiss this out of hand in the Arctic stations. Some of the amateur land stations on the continental USA have bad siting issues; though their impact is small. That's an empirical result, by the way.

Similarly; your cynicism in the OP is misplaced. Advocates for conventional climate science, like myself, have pointed out frequently that there is nothing preventing "skeptics" from publishing in the scientific literature. The authors of this paper are well known as critics of conventional climate science; and -- just like I and others have said -- they still get published. This is not surprising at all. What would be really surprising is a conspiracy to keep them out -- which is the claim of certain skeptics; not those of us who accept the mainstream.

The paper in this case is looking at a long standing unsolved puzzle; the difference between RSS and UAH satellite reconstructions of lower troposphere temperatures. This paper proposes a possible solution, and I have not yet had a close look at it myself. But it is it a testable hypothesis, this could be useful. What is interesting is that RSS and UAH datasets use exactly the same raw satellite data -- and the significant differences between them are entirely due to processing of data from different satellites into a single global gridded anomaly. I won't personally consider this puzzle solved until it is plainly seen where in the processing one or the other algorithm is failing. I don't have a strong feeling at this point on which of RSS and UAH is going to be most accurate.

We discussed this in the thread [thread=359434]Satellite temp data[/thread] recently; where you made the statement which struck me as very odd at the time, as follows:

Both satelite temperature reconstructions from UAH and RSS are in good agreement despite the difference in methods, which should say something about their robustness.

This paper (and my reply in the other thread, at [post=2470030]msg #4[/post]) show that in fact there are significant differences between RSS and UAH temperature reconstructions from the satellite data, which remain an active focus of attention in the scientific literature.

Cheers -- sylas

 

[Andre]

Similarly; your cynicism in the OP is misplaced. Advocates for conventional climate science, like myself, have pointed out frequently that there is nothing preventing "skeptics" from publishing in the scientific literature. The authors of this paper are well known as critics of conventional climate science; and -- just like I and others have said -- they still get published. This is not surprising at all. What would be really surprising is a conspiracy to keep them out -- which is the claim of certain skeptics; not those of us who accept the mainstream.

Climate-gate check Mann's email about the publication of Soon and Baliunas
https://www.physicsforums.com/showpost.php?p=2468688&postcount=294

We discussed this in the thread [thread=359434]Satellite temp data[/thread] recently; where you made the statement which struck me as very odd at the time,

This paper (and my reply in the other thread, at [post=2470030]msg #4[/post]) show that in fact there are significant differences between RSS and UAH temperature reconstructions from the satellite data, which remain an active focus of attention in the scientific literature.

Is an r2 of 91% (0.9087) not a good agreement?

Just plot the data and calculate yourself

http://vortex.nsstc.uah.edu/public/msu/t2lt/tltglhmam_5.2
http://www.remss.com/data/msu/monthly_time_series/RSS_Monthly_MSU_AMSU_Channel_TLT_Anomalies_Land_and_Ocean_v03_2.txt

 

[seycyrus]

Similarly; your cynicism in the OP is misplaced. Advocates for conventional climate science, like myself, have pointed out frequently that there is nothing preventing "skeptics" from publishing in the scientific literature.

Except for the well documented hostility towards those who propose alternative theories. The peer review process is becoming more and more suspect among the scientific community all the time. To claim that these problems do not manifest in the AGW community known for its disdain of opponents is a stretch. Such problems would be more commonplace is such a community, not less, imo.

The fact that a few get through is a testament to the resourcefulness and determination of the authors.

 

[sylas]

Climate-gate check Mann's email about the publication of Soon and Baliunas
https://www.physicsforums.com/showpost.php?p=2468688&postcount=294

That is an example of an atrocious paper that should not have been published no matter who wrote it. The scandal was significant, and most of the editorial board resigned over the issue and failures to address flaws in the journal's review processes. This has got nothing to do with a conspiracy to keep out skeptics, but a case where the review process in a journal failed quite spectacularly to keep out a genuinely dreadful paper. In fact, the conspiracy seems to have been in reverse -- not scientists working to subvert the process and keep out the skeptics, but skeptics working to subvert the process and let in skeptical papers without adequate review for methodological flaws. It's a good example of why we tend to put scare quotes around the word "skeptics".

The scandal was all out in the open well before the theft of emails, and it all hit the fan AFTER the email by Mann in Mar 11, 2003. In fact, events shows that Mann was completely correct in what he wrote in the emails.

If you want climate skepticism to be at all credible, you had better make sure you don't fall into the trap of merely assuming every paper by a skeptic is worth publishing. That would be just be the same error in reverse of anyone who merely presumed every paper by a skeptic was NOT worth publishing.

Generally speaking, the system used by science journals is rather more robust. You don't accept or reject papers in advance based on who wrote them. You look at the paper itself on its merits. The problem with Soon and Balinaus is a case where the review process failed. You judge that not by who wrote it, but what was written. Tackle the case on its merits. Don't presume that any given author can't write a good paper, or always writes a good one.

Is an r2 of 91% (0.9087) not a good agreement?

It misses the disagreements. These are gridded data sets. You cannot tell if they agree by converting the entire grid into a single global anomaly and looking for correlations in that alone.

Read your own cited paper. It will put you straight on the need for more than this simplistic one dimensional comparison.

Just plot the data and calculate yourself

This is a good demonstration of why doing things for yourself can be a tad unreliable. You aren't plotting the datasets; you are plotting one number; and the wrong number for looking at where the the two datasets diverge.

Cheers -- sylas

 

[Andre]

it occurs to me that the main sin of Soon and Baliunas was to disagree with Mann. As the medieval warm period had http://epw.senate.gov/hearing_statements.cfm?id=266543 and they just compiled some hundreds or so studies that mentioned proof of a medieval warm period. I don't think that everybody agrees that it was a bad paper.

 

[sylas]

it occurs to me that the main sin of Soon and Baliunas was to disagree with Mann. As the medieval warm period had http://epw.senate.gov/hearing_statements.cfm?id=266543 and they just compiled some hundreds or so studies that mentioned proof of a medieval warm period. I don't think that everybody agrees that it was a bad paper.

Nearly everybody agrees; certainly most of the editorial board. It was not a case merely of disagreement in the conclusion, but of gaping holes in methodology.

Given the public statements of editors and the devastating published rebuttal pointing out its errors, I'm inclined to say that there really was a bad problem in how the review was handled, and that the paper should not have been published.

Note that the rebuttal is not a case of just giving a different conclusion and different arguments. It was specifically showing where the actual argument of the paper failed. Have you looked at the original paper and the responses, and the comments of the editors?

Cheers -- sylas

 

[Xnn]

These guys are still pointing to CO2 for the warming trend!

They are calling it a bias because it's occurring near the surface as opposed to the higher elevations. However, some of us already understand that greenhouse gases result in a cooling of the upper atmosphere.

The rate of heat loss to space is dependent on
several factors, including cloudiness and the local atmospheric
concentrations of carbon dioxide and of water vapor
[e.g., Pielke, 2002]. Under cloudy conditions, cooling is
much less. An atmosphere with higher concentrations of the
greenhouse gases, CO2 and H2O, also reduces the cooling at
night. Consequently if, for instance, there is a long-term
positive trend in greenhouse gas concentrations or cloudiness
over the observing site, it may introduce an upward
bias in the observational record of minimum temperatures
that necessarily will result in an upward bias in the longterm
surface temperature record.

[16] Because of changes to the atmosphere over the past
century, there are several reasons why we should expect the
nighttime cooling in the lower atmosphere to have been
reduced. One reason for this is that carbon dioxide concentrations
have increased, such that the effect of well-mixed
greenhouse gas concentrations on near-surface temperature
measurements has also increased. This increase is also
expected to be higher for growing urban and industrial locations
where carbon dioxide can locally accumulate when the
large-scale wind flow is weak. An increase of water vapor
over time would have the same effect. Also, an increase of
cloudiness has been reported which has the effect of reducing
nighttime cooling [Karl et al., 1997].

And then there is this statement:

Physically, the nighttime boundary layer is not a good
place to detect the accumulation of heat. While its temperature
response to forcing is greater because of the inverse
depth dependence mentioned above, the stable boundary
layer is so shallow in most cases that it represents an
insignificant mass of the atmosphere. Additionally, as shown
by Walters et al. [2007], any positive forcing such as
additional greenhouse gases destabilizes the boundary layer,
increases its depth, and mixes warm air aloft to the surface.
Thus, the warming is amplified at the surface but represents a
redistribution of heat rather than accumulated heat from the
additional forcing.

First; they call the ground level boundry layer an insignificant portion of the atmosphere, but that is where we all live and I've never seen a glacier floating in the sky either.

Second; Global warming is coming from the atmosphere trapping heat near the surface. This is especially true at night. Everyone should understand this.

I don't accept these guys objections; they need to be more pratical.

 

[sylas]

These guys are still pointing to CO2 for the warming trend!

They are calling it a bias because it's occurring near the surface as opposed to the higher elevations. However, some of us already understand that greenhouse gases result in a cooling of the upper atmosphere.

Careful... this paper is not about the upper atmosphere. The physical expectations are that in general, the lower atmosphere should warm more than the surface. Cooling is only way up above the tropopause.

Measurements of the atmosphere are tricky, and this paper is about issues in the lower atmosphere which are still being sorted out. It's worth noting the the expectation of stronger warming in the lower atmosphere than the surface is not specifically related to greenhouse effect, but should arise for almost any forced warming, due to effects on lapse rate.

The stratospheric cooling, on the other hand, is particularly associated with greenhouse effects.

Cheers -- sylas

 

[DSS]

I am surprised to see debate here using terms like "warming" which have been shown to be meaningless:

http://www.fys.ku.dk/~andresen/BAhome/ownpapers/globalT/globalT_JNET2007.pdf

Abstract
Physical, mathematical, and observational grounds are employed to show
that there is no physically meaningful global temperature for the Earth in
the context of the issue of global warming. While it is always possible to con-
struct statistics for any given set of local temperature data, an infinite range
of such statistics is mathematically permissible if physical principles provide
no explicit basis for choosing among them. Distinct and equally valid sta-
tistical rules can and do show opposite trends when applied to the results of
computations from physical models and real data in the atmosphere. A given
temperature field can be interpreted as both ‘‘warming’’ and ‘‘cooling’’ simul-
taneously, making the concept of warming in the context of the issue of
global warming physically ill-posed.

 

[sylas]

I am surprised to see debate here using terms like "warming" which have been shown to be meaningless:

Um... no it hasn't. That rather odd little paper is saying that there's no such thing as a "global temperature"; which is not the same thing.

Warming is not obtained as a change in a measured global temperature, so warming does not use the notion of global temperature.

Global warming is obtained through "anomalies". In brief, you don't use global temperature, but LOCAL temperature. And then find how temperature changes locally. This makes perfect sense. The local change in temperature is the "anomaly", and global warming is a measure of averaged anomalies; not averaged temperatures.

Cheers -- sylas

 

[DSS]

The lack of a global temp. is just one aspect of the argument in the paper. The main point is that temperature and changes in temperature are simply not a meaningful way to measure the Global energy balance. This shows that all talk of keeping Global temperature increase below 2 degrees, etc. is meaningless. You advocate a procedure that has all the same problems (Actually, I don't think you are advocating a procedure. If you were you wouldn't need the quotes around anomalies.)

If we directly measure the Planet's energy balance, then it is clear that net energy absorbed has been decreasing since the turn of the century:

http://legacy.signonsandiego.com/uniontrib/20060824/news_lz1c24moon.html

 

[Andre]

Thaks DSS that is consistent with Palle et al EOS 2006. Palle did not check the real correlation between temperature and albedo, otherwise he would have written quite a different article. I made a thread about that once.

 

[sylas]

Sorry; I was working on this reply and then put it aside and forgot about it. Better late than never.

The lack of a global temp. is just one aspect of the argument in the paper. The main point is that temperature and changes in temperature are simply not a meaningful way to measure the Global energy balance. This shows that all talk of keeping Global temperature increase below 2 degrees, etc. is meaningless. You advocate a procedure that has all the same problems (Actually, I don't think you are advocating a procedure. If you were you wouldn't need the quotes around anomalies.)

Actually, I am advocating the use of anomalies, and I agree that this is not a way to measure energy balance. The quote marks were to indicate a term being defined. Anomalies don't give you energy balance, but rather warming, or cooling. It quantifies change in temperature, not temperature itself.

If we directly measure the Planet's energy balance, then it is clear that net energy absorbed has been decreasing since the turn of the century:

The decrease in absorbed energy (increase in albedo, or reflectance) that you see in that paper is an error caused by problems with the telescope; which has since been corrected.

Furthermore, that is not a direct measure of energy balance. It is an indirect way to measure how much shortwave radiation is emitted from the Earth, which is light reflected from the Sun. The research you are citing does this indirectly, by looking at "Earth'shine", or measured Earth light reflected from the Moon. The results obtained by this method can be compared with results obtained by looking directly at shortwave radiation coming from the Earth measured with satellites.

Knowing this shortwave emission is not the whole energy balance, but it is certainly an important contribution to understanding energy balance or imbalance for the Earth. It would allow us to infer how much of the incoming solar input is absorbed by the Earth.

The particular work you cite has a very curious glitch in the twenty first century, where the Earthshine inference indicates a sharp rise in the absorbed energy. This was singled out by a number of critics as indicating something wrong with the work; whereas Palle himself originally emphasized the rise as a discovery. It turns out that the critics were correct; the anomalous result was an artifact of the telescope being used; which is explained and resolved in Palle's most recent publication.

• Pallé, E., P. R. Goode, and P. Montañés-Rodríguez (2009), http://www.agu.org/pubs/crossref/2009/2008JD010734.shtml, in J. Geophys. Res., Vol 114, p D00D03, doi:10.1029/2008JD010734. Preprint, pdf.

With this latest publication, and with refinements of the reflectance estimates from the direct satellite measurements, all the various results are consistent to within normal uncertainties. There is no decrease in the absorbed energy any more, it is roughly constant over recent times, with a slight increase in absorbed energy going back a bit further.

The satellite reflectance measurements that Earthshine estimates may be compared with are reported at

• Loeb, N.G. et. al. (2007) Multi-Instrument Comparison of Top-of-Atmosphere Reflected Solar Radiation, in J. of Climate, 20(3), Feb 2007, pp 575-591, doi: 10.1175/JCLI4018.1. Preprint, http://asd-www.larc.nasa.gov/~tak/wong/f22m.pdf .

Also Andre:

Thaks DSS that is consistent with Palle et al EOS 2006. Palle did not check the real correlation between temperature and albedo, otherwise he would have written quite a different article. I made a thread about that once.

There are very good reasons to be confident he would certainly not have written a different article. Correlations are a particularly weak form of argument when you know there are many different factors involved. But this is beside the point now, of course, as the paper you are citing and the previous work were all incorrect because of the problem with telescopes.

Cheers -- sylas

 

[DSS]

"The quote marks were to indicate a term being defined."

But you don't give a definition, so the statement is meaningless.

The response seems to avoid addressing the fundamental question. I post this summary that gives a good overview of the situation:

The article below is from the Space special interest group of the high IQ society Mensa.

Mentor note: Invalid reference has been deleted

 

[sylas]

"The quote marks were to indicate a term being defined."

But you don't give a definition, so the statement is meaningless.

Actually, I do. The post where I introduced the term ([post=2486548]msg #14[/post]) also briefly explains what it means. An anomaly is a measure of how far temperatures have changed from a baseline climatology. They are used to measure warming, because even when temperature vary significantly within a localized region, due to altitude or land cover or prevailing winds or anything of the kind, the anomaly tends to be very similar across large areas.

Understanding anomalies is pretty important in this whole topic, as they are a standard measure for quantifying changes in climate, both local and global. A more thorough definition of anomalies, and why they are used, is also available at the background information FAQs at NCDC. See http://www.ncdc.noaa.gov/oa/climate/research/anomalies/index.html .

Cheers -- sylas

 

[Xnn]

Sylas; thanks for the great post.

I got a chuckle from the comments in AMS paper about running out of fuel:

Commonly used statistical tools applied to the CERES Terra data reveal that in order to detect a statistically significant trend of magnitude 0.3 W m−2 decade−1 in global SW TOA flux, approximately 10 to 15 yr of data are needed. This assumes that CERES Terra instrument calibration remains highly stable, long-term climate variability remains constant, and the Terra spacecraft has enough fuel to last 15 yr.

DSS;

You should review the forum guidelines. That Mensa article has lots of errors some of which should be obvious:

The Galactic Orbit of the Solar System every 240,000 million years...

 

[DSS]

"An anomaly is a measure of how far temperatures have changed from a baseline climatology."

The use of 'baseline' here is misleading, since the selected time is arbitrary.

Defining "Anomaly" - "deviation from the normal or common order or form or rule"

Similarly, we see the term "Anomaly" used to stand in for "change in temperature."

Tortured language is usually a sign of convoluted thinking. Simplicity is a sign of good science.

The main point of my initial post was that aggregation of temperatures could produce arbitrary results and therefore the only meaningful measure was energy balance. If we compare:

http://www.ncdc.noaa.gov/oa/climate/research/anomalies/index.html

and

http://www.drroyspencer.com/latest-global-temperatures/

or

http://www.drroyspencer.com/2009/01/daily-monitoring-of-global-average-temperatures/

we get a different picture of 'temperature change' since 1979. I therefore rest my case.

In terms of practical implication of these arguments, the COP15 talks have flopped and the chance of any binding agreements is dropping rapidly. As proponents of 'global warming' have been forced to release their data, their claimed 'evidence for AGW' is disappearing:

http://climateaudit.org/2009/09/27/yamal-a-divergence-problem/
Finally, I find the censorship here unacceptable and therefore this will be my final post.

 

[sylas]

"An anomaly is a measure of how far temperatures have changed from a baseline climatology."

The use of 'baseline' here is misleading, since the selected time is arbitrary.

Yes, the baseline is arbitrary. Different datasets use different baselines, and aligning them to a common baseline is straightforward. We do it all the time.

Tortured language is usually a sign of convoluted thinking. Simplicity is a sign of good science.

Scientists should never use technical jargon. Got it.

The main point of my initial post was that aggregation of temperatures could produce arbitrary results and therefore the only meaningful measure was energy balance. If we compare:

http://www.ncdc.noaa.gov/oa/climate/research/anomalies/index.html

and

http://www.drroyspencer.com/latest-global-temperatures/

or

http://www.drroyspencer.com/2009/01/daily-monitoring-of-global-average-temperatures/

we get a different picture of 'temperature change' since 1979. I therefore rest my case.

Personally, I think the major reason for the difference is that they are measuring different quantities over radically different time spans.

Dr Spencer -- who ALSO uses anomalies, just like the rest of us, by the way -- is showing the temperature anomalies in the troposphere since 1980; which is his major area of research. The NCDC page is showing temperature anomalies at the surface since 1880. That extra 100 years might be what makes it look a bit different.

Furthermore; the surface and the troposphere aren't the same thing and the anomalies are not the same either. But if you actually compare them over the same spread of years, the correlation is strong; as you should expect.

Finally, I find the censorship here unacceptable and therefore this will be my final post.

I hope you find what you are looking for somewhere else then.

Cheers -- sylas